Ski body made of plastics

ABSTRACT

There is disclosed and claimed a novel ski body made of plastics, which consists of at least two parts with equal or different length, width and thickness, depending on the dimensions of the complete ski, the number of parts and the dimensions of the respective other parts. These parts are arranged in the form of layers one on top of the other. All parts of the ski body are able to bear mechanical stress.

[11] 3,894,745 [4 1 Juiy 15, 1975 United States Patent [191 Heim et a1.

3.635 482 1/1972 Holman.......1..,........... 280/1 1.13 10/1972 3 FOREIGN PATENTS OR APPLICATIONS 1 1 SKI BODY MADE OF PLASTICS 3.698.731 lost et a1 280/11.1

Inventors: Peter Heim, Ulm; Dietrich Schleede,

Wiesbaden, both of Germany Hoechst Aktiengesellschaft,

Austria...'...H.......H.,... Germany............ France1v...........,v...4..... Italy Canadam. Austria..,....H.1,.H........H

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Primary Examiner- David Sc honberg Assistant Examiner-David M. Mitchell Attorney, Agent, or FirmCurtis, Morris 8: Safford Foreign Application Priority Data May 14.1971

Germany..............H.......... 2124061 ABSTRACT r @Mde a nb m m swu va n dm o b sm iom h knh k VMmE k n np amam wfmc m MC mm v t S S n fl a km dh S Re m b m m wei .m m dw e n m mm n w flo m u 3 TM mm Rm L HNBU .LCLI. 1& 0 oo FA fl w Lm 3 c, mow A1 0 .H 8 2 u 8 S 1 1m I S k UhF H M 555 References a of parts and the dimensions of the respective other UNITED STATES PATENTS parts. These parts are arranged in the form of layers one on top of the other. All parts of the ski bod able to bear mechanical stress.

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FIG. 4c

SKI BODY MADE OF PLASTICS This is a continuation of application Ser. 252,856, filed May 12, 1972, now abandoned.

The present invention relates to a ski body made of plastics.

Skis for various purposes, which are constructed in a way common nowadays (made of wood, metal, plastics), require for their manufacture a high expenditure of working time, working power and working means depending on their construction and the materials used. The manufacture also depends on a great number of suppliers, and high expenditure has to be made for the procurement, storage and working of the materials used.

A certain rationalization in the manufacture of skis has been reached by the introduction of ski cores made of polyurethane (cf., for example, French Patent No. l,403,059). Later on. skis made of solid plastics material on the basis of integral and/ or structural foam were developed (German Offenlegungsschrift No. l,809,0l 1; German Utility Model No. 7020.835). These skis made of integral and/or structual plastics foam, which are manufactured according to a single processing step, do not meet the requirements of highstrcss skis, as the essential properties. such as elasticity, stiffness in flexure, torsion stiffness. damping properties, and deformation behavior of skis having a length exceeding I meter are not satisfactory.

Longer skis which have to bear a higher stress cannot do without additional reinforcing elements. This is true for skis made of wood, metal and plastics. So far, the reinforcing elements have been applied onto the outer surfaces of the skis on principle in the form of thin layers. for example, in the form of thin sheets of alloyed aluminum or plastic having a glass fiber reinforcement (glass fibers embedded into epoxide resins). As against that, the ski core between the reinforcing layers, which consists of wood or plastics material, has to bear only a minor mechanical stress. The ski running surface designed to give good sliding properties and the upper ski surface developed for a decorative look do not have to bear any mechanical stress, either.

The present invention provides a ski body made of plastics consisting of two or several, preferably two, parts, the length, width and thickness of which is the same or different and depends on the dimensions of the complete ski and on the number of parts and on the dimensions of the respective other parts, the parts being arranged in the form of layers one on top of the other, wherein the connecting surfaces between two parts each, seen in a cross-sectional view, may have different profiles, and wherein the adjacent parts are connected with one another by means of gluing, injection moulding or injectionfoaming.

FIG. 1a is a longitudinal sectional view of a ski eonstructcd in accordance with one embodiment of the present invention;

FIGS. lb-le are transverse sectional views of four related embodiments of the present invention;

FIG. 2 is a sectional view similar to FIG. lb, but showing the provision of longitudinal hollow tubes formed in the ski parts;

FIG. 3 is a transverse sectional view of another embodiment of the present invention;

FIGS. 4u4d are transverse sectional views of skis constructed in accordance with another embodiment of present invention, using various reinforcing elements therein;

FIG. 4e is a partial perspective view, with parts broken away, of another embodiment of the present invention; and

FIG. 5 is a transverse sectional view of yet another embodiment of the present invention.

Various types of cross-sections of the ski body according to the invention will now be described, by way of example only, with reference to the accompanying drawings, in which FIG. 1 a represents a longitudinal section through a ski body according to the invention consisting of two parts, with the upper part I and the lower part 2. The extensions of the two parts are not limited to the dimensions shown. The length and/or width and/or thickness of the parts may be different and are limited only by the dimensions of the complete ski. Besides, the dimensions of the individual parts with respect to one another depend upon the properties desired of the complete ski.

A choice of different cross-sections for various possibilities to design the connecting surfaces between the ski body parts is represented in FIG. lb to 1e. In this case, essential properties are influences by a different design of the connecting surfaces to a higher degree than in the case ofa smooth connecting surface, for example, properties such as elasticity, stiffness in flexure and torsion stiffness, depending on the moment of resistance or inertia.

The parts of the ski body of the invention may consist of thermoplastic or duroplastic materials, the plastics material being a solid or a foamv As examples for thermoplastic materials to be used according to the invention, there may be mentioned polystyrene, polyacrylonitrile, polyacetals, polyethylene and other polyolefins and copolymers thereof, for example, copolymers of ethylene with propylene or ethylene with acetals, besides, modified polystyrenes, for example acrylonitrilebutadiene-styrene polymers, or polyesters, such as polyglycol terephthalate, and for duroplastic materials, polyurethanes.

The individual parts of the ski body may consist of different plastics materials, and it is also possible to connect parts made of foamed plastics material with those consisting of solid plastics material.

The individual parts of the ski body are manufactured by way of injection moulding or injectionfoaming (injection-moulding of plastics containing propellants) in special moulds having the shape of the respective ski body part. They are connected with one another by gluing or, preferably, by moulding or foaming together. The former process can be effected by using suitable adhesives or solvents. In the latter case, an adjacent part is added by way of injection-moulding or injection-foaming to a part manufactured before by using a mould, the shape of which is extended by the respective additional ski body part.

A special variant of the former process of gluing the ski body parts together comprises gluing parts which show, in their cross-section, grooves running lengthwise. This possibility is shown, for example, in FIG. 2. In this case the grooves have a semicircular crosssection, thus forming tubes of a circular cross-section 3, as the grooves of the two ski body parts 1 and 2 are arranged exactly one on top of the other. In this way various hollow spaces are obtained, the crosssection of which may show any shape.

A preferred variant of foamed parts of the ski body according to the invention is represented by parts consisting of a large-cell core having a low density 4, 4a and a marginal zone of a high density 5, 5a, the thickness of which may be influenced in accordance with the respective process. and the properties of which are similar to those of solid material (integral or structural foam). The particular advantages of this variant are to be seen in the saving of weight and in the improvement of the mechanical properties. By combining two or several ski parts consisting of integral or structural foam (multicoque construction), these properties are essentially improved. An example for a ski body comprising two ski parts, each consisting of an integral foam, is illustrated by the cross-sectional diagram in FIG. 3. The variation in dotting is to illustrate the different distribution of the density of material.

Another preferred variant is obtained by combining the modes of construction of FIGS. 2 and 3, Le. the ski body parts are constructed in a Way that they show both a large-cell core of a low density, as well as a marginal zone of a high density. and longitudinal grooves. Such a design of the ski body has the advantage. besides the saving of weight, that the moment of resistance is increased, which results in an improved stiffness in flexure and torsion stiffness, owing to the enlargement of the high-density marginal zone by geometrical means (i.e. by the grooves).

Another preferred variant of the ski body according to the invention is given by the possibility that in one or two or several of the ski body parts there are additional reinforcing elements which may, optionally, project into the adjacent ski body part.

These reinforcing elements may be in the form of laminae or sheets, which can also be interrupted and profiled, for example, in the form of a corrugated plate, or profiles having a different geometrical structure, for example. a T, a double T 6 or a U cross-section 7, or in the form of tubes 8, of wires 9, which may, optionally, be prestressed. Examples for profiles of this kind are illustrated by cross-sectional diagrams in FIGS. 4a to 4e.

In FIG. 4e, the reinforcing element consists of a plate 10 with semicircular cambers (corrugations) 11 in the longitudinal direction. which cover semi-circular grooves I2 in the subjacent ski body part, as can be seen in the cross-section. In the planes 13 between the cambers I l of the plate, there are slots 14 which enable a connection of the upper and the lower ski body parts when the adjacent part is injection-moulded onto the part manufactured before. The slots 14 are not required, if the two ski body part 1 and 2 are to be glued to the plate 10.

The reinforcing elements may consists of metals, for example, steel, preferably aluminum alloys of a high strength and elasticity, or of glass fivers or glass fibers connected by plastic material. for example, polyester or epoxy resins; a ski body may also contain two or several reinforcing elements of a different shape and/or a different cross-sectional profile, and/or of a different material.

The properties of the complete ski are essentially influenced by the choice of the reinforcing elements.

A reinforcement can also be included already in the plastic raw material, for example. by the introduction of glass fibers.

FIG. 40 is a cross-sectional view of a combination of a specially designed connecting surface between the top part of the ski body 1 and its bottom part 2, with wires 9 as reinforcing elements.

In order to add further equipment to the ski body of the invention, it can be provided with accessories, as illustrated by a cross-sectional view in FIG. 5, such as steel edges l5, 16, a protection for the ski points and engs, a running surface layer 17 and a top surface layer 18, as well as a binding mounting plate 19. Besides the possibility of subsequently mounting the accessories to the ski body, there is also the possibility of introducing individual or several of these accessories into the respective mould, in the course of the manufacture of the ski body parts, and connecting them with the ski body part by means of injection-moulding or injectionfoaming. By choosing suitable plastics materials for the individual ski body parts. the mounting of accessories. such as the upper edges of skis, the ski top surface layers, the running surface layer, the protection for the ski points and ends, or the steel edges, is no more necessary. Thus. for example, the choice of a plastic material having good sliding and wearing properties for the bottom ski body part makes the mounting of separate running surface layers unnecessary, which are common otherwise.

By an appropriate design of the mould for the lower part of the ski body it is possible to construct the running surface of the complete ski in a way that the subse quent mounting of running surface layers having a particular profile, such as a step or scale structure, for climbing and sliding skis, for example touring and cross-country skis, is no more necessary.

The ski body of the invention permits the optimum utilization of the properties of the plastics materials. and all parts of the ski body are able to bear mechanical stress.

What is claimed is:

l. A ski body forming substantially the entire ski and adapted to bear all of the mechanical stresses in the ski during use comprising at least two independently formed plastic layers having generally complementary surface portions located adjacent each other and secured in superimposed relation to one another with one layer being on top of the other; at least one elongated reinforcing element between said layers for absorbing torsional and bending forces in the ski when in use; at least one of said generally complementary surfaces having at least one elongated recess formed therein which receives said reinforcing element; said one generally complementary surface having a plurality of Iongitudinal recess formed therein having generally semicylindrical configurations opening towards the other of said complementary surfaces and said reinforcing element comprising a plate having generally semicylindrical corrugations formed therein and received in said recesses, said plate having a plurality of apertures formed therein between said corrugations and said layers being joined to each other through said apertures.

2. The ski body as defined in claim I wherein said plastic layers are formed of a foamed plastic material having a large cell core of low density and a marginal zone of high density.

3. The ski body as defined in claim 1 wherein said plastic layers are formed from plastic materials selected from the group consisting of thermoplastic and/or duroplastic materials.

4. The ski body as defined in claim 3 wherein said plastic layers are formed of different plastic materials. I 8 

1. A ski body forming substantially the entire ski and adapted to bear all of the mechanical stresses in the ski during use comprising at least two independently formed plastic layers having generally complementary surface portions located adjacent each other and secured in superimposed relation to one another with one layer being on top of the other; at least one elongated reinforcing element between said layers for absorbing torsional and bending forces in the ski when in use; at least one of said generally complementary surfaces having at least one elongated recess formed therein which receives said reinforcing element; said one generally complementary surface having a plurality of longitudinal recess formed therein having generally semicylindrical configurations opening towards the other of said complementary surfaces and said reinforcing element comprising a plate having generally semicylindrical corrugations formed therein and received in said recesses, said plate having a plurality of apertures formed therein between said corrugations and said layers being joined to each other through said apertures.
 2. The ski body as defined in claim 1 wherein said plastic layers are formed of a foamed plastic material having a large cell core of low density and a marginal zone of high density.
 3. The ski body as defined in claim 1 wherein said plastic layers are formed from plastic materials selected from the group consisting of thermoplastic and/or duroplastic materials.
 4. The ski body as defined in claim 3 wherein said plastic layers are formed of different plastic materials. 